Defolliculated is a novel spontaneous mouse mutation that maps to chromosome 11 close to the type I keratin locus. Histology shows abnormal differentiation of the sebaceous gland, with the sebocytes producing little or no sebum and undergoing abnormal cornification. The hair follicles fail to regress during catagen leading to abnormally long follicles. In contrast the hair shafts are shorter than normal, suggesting altered differentiation or proliferation of matrix cells during anagen. The shafts emerge from the follicle with cornified material still attached. The dermis contains increased numbers of immune cells, including T cells (CD4-positive), macrophages, and mast cells, at all time points examined. Complete elimination of all pelage and tail follicles occurs after two to three hair cycles, apparently by necrosis. Defolliculated may be a useful model for determining further functions of the sebaceous gland, and for understanding the regulation of catagen and hair follicle immunology.

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SUMMARYHaematological findings in 26 domestic fowl and 17 cranes with confirmed Mycobacterium avium infection were compared with normal values from the species concerned. Heterophils and monocytosis occurred frequently in the infected birds; in many cases very large numbers of these cells were present. Haematological findings were related, where possible, to the results of the intradermal tuberculin test and the haemagglutination test. It was concluded that haematological testing has a useful role in both diagnosis and screening for avian TB infections in the species studied.